Retool is an AI-powered platform designed to help developers build custom internal tools quickly. The platform provides a drag-and-drop interface that allows developers to connect with databases and APIs, enabling them to build user interfaces (UI) with ease. Key features include pre-built components for adding inputs, tables, buttons, etc., the ability to write custom JavaScript, and querying capabilities with SQL, GraphQL, and others. It also supports integration with a wide range of data sources and services.